Sporadic ALS with early-onset respiratory failure is not associated with IGHMBP2 gene mutations

Few distinct motor neurone disease (MND) variants-for example, familial amyotrophic lateral sclerosis (fALS) and spinal muscular atrophy (SMA)-are caused by definitive gene mutations. Spinal muscular atrophy with respiratory distress type 1 (SMARD1; 11q13-q21) is a specific and rare variant of infantile SMA, caused by homozygous mutations in the immunoglobulin mu binding protein 2 (IGHMBP2) gene. 4 SMARD1 is clinically characterised by diaphragmatic paralysis and progressive muscular weakness with predominantly distal lower limb muscle involvement, intrauterine growth retardation, prematurity, foot deformities and autonomous symptoms.